<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>jQuery</title>
</head>
<body>
    <script>
        var jQuery = function (sel, cont) {
            // return new jQuery
            // return new jQuery()
        }
        console.dir(jQuery);
        jQuery.fn = jQuery.prototype
        var init
        init = jQuery.fn.init = function (sel, cont, root) {
            console.log('我是fn的init');
        }
        init.prototype = jQuery.fn = jQuery.prototype
        console.dir(jQuery);
        window.jQuery = window.$ = jQuery
        console.dir(new jQuery);
    </script>
</body>
</html>